The servicing of vehicle engines is becoming increasingly important because of road safety considerations and the public awareness of automotive emissions on the environment. In addition, the engines of current vehicles are becoming more difficult and complicated to diagnose and analyze. As a result, one object of the present invention is to provide an automated and rapid diagnostic device which will reduce the cost of labor involved in diagnosing vehicle engines.
Other objects of the invention are:
(1) TO PROVIDE PRECISE AND OBJECTIVE EVALUATION OF MALFUNCTION TO AVOID CUSTOMER RETURNS;
(2) TO DISPLAY DATA ACCUMULATED FROM A VEHICLE ENGINE IN AN EASY-TO-UNDERSTAND FORM;
(3) TO PROVIDE AN IMPROVED DEVICE FOR DISPLAYING ENGINE RPM, DWELL AND CYLINDER TIMING BY DIRECT DIGITAL MEASUREMENT;
(4) TO PROVIDE A DEVICE FOR DISPLAYING THE VALUES OF ENGINE PARAMETERS ON A CATHODE RAY TUBE DISPLAY MORITOR IN ALPHABETIC, DIGITAL AND GRAPHICAL FORM;
(5) TO PROVIDE A CATHODE RAY TUBE DISPLAY MONITOR OF THE FOREGOING TYPE IN WHICH THE HISTORY OF AN ENGINE PARAMETER IS DISPLAYED AS A FUNCTION OF TIME;
(6) TO PROVIDE AN IMPROVED DEVICE IN WHICH RELATED VEHICLE ENGINE TESTS ARE GROUPED TOGETHER AND DISPLAYED SIMULTANEOUSLY ON A CATHODE RAY TUBE DISPLAY MONITOR, AND IN WHICH THE TESTS ARE SEQUENCED ONE AFTER ANOTHER IN AN AUTOMATIC MANNER;
(7) TO PROVIDE A SEQUENCING MODE OF OPERATION OF THE FOREGOING TYPE IN WHICH DATA IS REMEMBERED BY THE APPARATUS FROM ONE TEST GROUPING TO ANOTHER;
(8) TO PROVIDE AN IMPROVED DEVICE FOR DISPLAYING ENGINE PARAMETER VALUES FOR EACH CYLINDER OF A MULTICYLINDER ENGINE;
(9) TO PROVIDE A MEANS OF DISPLAYING THE SPEED OF A VEHICLE ENGINE ON A CATHODE RAY TUBE DISPLAY MONITOR BY MEANS OF A BAR GRAPH;
(10) TO PROVIDE AN AUTOMATIC VEHICLE ENGINE DIAGNOSING DEVICE CAPABLE OF REMEMBERING CALIBRATION CONSTANTS AND AUTOMATICALLY PROCESSING THE DATA RECEIVED FROM THE ENGINE BY LINEARIZING THE VALUE OF THE DATA;
(11) TO PROVIDE AN IMPROVED VEHICLE ENGINE DIAGNOSING DEVICE CAPABLE OF DECIDING WHETHER COMPONENTS OF THE ENGINE ARE IN GOOD WORKING ORDER OR SHOULD BE REPLACED;
(12) TO PROVIDE AN IMPROVED DEVICE WHICH IS AUTOMATICALLY CAPABLE OF MEASURING THE POWER BALANCE OF A VEHICLE ENGINE;
(13) TO PROVIDE AN AUTOMATIC POWER BALANCE DEVICE OF THE FOREGOING TYPE IN WHICH THE SPEED OF THE ENGINE OVER SEVERAL ENGINE REVOLUTIONS IS AVERAGED DURING THE POWER BALANCING PROCEDURE;
(14) TO PROVIDE AN IMPROVED APPARATUS FOR MEASURING THE PARAMETERS OF AN ENGINE BY AN ANALOG CIRCUIT WHICH IS AUTOMATICALLY SET TO THE PROPER RANGE DEPENDING ON THE VALUE OF THE PARAMETER BEING MEASURED; AND
(15) TO PROVIDE AN IMPROVED VEHICLE ENGINE TESTING DEVICE WHICH IS CAPABLE OF STORING MAXIMUM AND MINIMUM VALUES OF THE ENGINE PARAMETERS AND OF DISPLAYING THE VALUES STORED.
(16) TO PROVIDE AN IMPROVED VEHICLE TESTING DEVICE CAPABLE OF DISPLAYING A VALUE IF AN ENGINE PARAMETER LIES WITHIN AN ACCEPTABLE RANGE AND CAPABLE OF DISPLAYING A SYMBOL IF THE ENGINE PARAMETER LIES OUTSIDE THE ACCEPTABLE RANGE.